Google Deep MindProprietary

Gemini 3.1 Flash TTS (preview)

Name: Gemini 3.1 Flash TTS (preview)
Author: Google Deep Mind

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A text-to-speech synthesis model developed by Google DeepMind. It generates high-quality audio from text input.

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Parameters

Undisclosed

Context Window

License

Proprietary

Release Date

2026-04-16

Japanese Language Capability

✅High-Quality JP

Multilingual model with strong Japanese language processing capabilities.

API Pricing

API pricing for this model is not yet available

Strengths

Weaknesses

Use Cases

Deep Analysis

Arena Elo

1211

#2 overall on Artificial Analysis TTS leaderboard

Input Price

$1.00/1M tokens

via Google AI Studio

Output Price

$20.00/1M tokens

audio output tokens

Languages Supported

70+

including major global languages

Latency

<200ms

for short-form content generation

Audio Tags

200+

for expressive control via inline natural language tags

Strengths

・Unmatched expressiveness with 200+ inline audio tags for precise voice control.
・Low latency (<200ms) enabling real-time interactive applications.
・Broad multilingual support covering 70+ languages for global use.

Weaknesses

・Preview status with potential instability, no SLA, and possible breaking changes.
・Limited voice library with only 30 preset voices and no voice cloning support.
・Significant quality degradation for long-form content over one minute, with 90% failure rate observed.

Competitor Comparison

Model	Arena	SWE	GPQA	Price
ElevenLabs Flash	#3	N/A	N/A	$0.050/1K chars
OpenAI TTS-1-HD	Below top 10	N/A	N/A	$0.030/1K chars

Overview

Gemini 3.1 Flash TTS, released by Google DeepMind in April 2026, is a preview text-to-speech model designed for high-fidelity, expressive speech synthesis. It stands out with granular control through 200+ inline audio tags, allowing developers to direct vocal style, pacing, and emotion directly in text prompts. The model supports 70+ languages, features native multi-speaker dialogue, and includes SynthID watermarking for AI-generated content detection. Positioned as a cost-effective alternative to premium TTS services, Gemini 3.1 Flash TTS excels in short-form applications like real-time narration, accessibility tools, and e-learning content. However, its preview nature and limitations in long-form stability and voice diversity position it primarily for prototyping and specific use cases where expressiveness and low cost outweigh production robustness needs.

Benchmarks & Performance

Gemini 3.1 Flash TTS demonstrates strong performance in short-form benchmarks but shows weaknesses in long-form consistency. Here's a detailed comparison with key competitors: | Metric | Gemini 3.1 Flash TTS | ElevenLabs Flash | OpenAI TTS-1-HD | |--------|----------------------|------------------|------------------| | **Arena Elo** (Artificial Analysis) | 1211 (#2) | #3 | Below top 10 | | **Latency** (short clips) | <200ms | ~250ms | ~300ms | | **Languages** | 70+ | 32+ | 15+ | | **Expressive Tags** | 200+ inline tags | Limited via voice settings | None | | **Price per 1K characters** | ~$0.012 | ~$0.050 | ~$0.030 | | **Voice Cloning** | No | Yes | No | | **Long-form Stability** | Degrades after 1 minute (90% failure) | Stable | Stable | *Benchmarks sourced from Artificial Analysis TTS leaderboard and independent reviews.* The model's Elo score of 1211 ranks it second overall, indicating high naturalness in blind tests. However, real-world tests reveal a critical flaw: quality degrades significantly for content over one minute, with mumbled articulation and lost clarity in 90% of long-form generations.

Detailed Comparison

**Gemini 3.1 Flash TTS vs ElevenLabs Flash:** - **Price:** Gemini is ~4x cheaper at ~$0.012/1K chars vs ElevenLabs' ~$0.050/1K chars. - **Control:** Gemini offers superior granular control via 200+ inline audio tags; ElevenLabs relies on voice presets and limited style settings. - **Quality:** ElevenLabs maintains consistent quality for long-form content and supports voice cloning, making it better for premium use cases. Gemini excels in short-form expressiveness but fails on long-form stability. - **Use Case:** Choose Gemini for budget-conscious, high-volume short audio with expressive needs; choose ElevenLabs for voice cloning, consistent long-form, or premium brand voices. **Gemini 3.1 Flash TTS vs OpenAI TTS-1-HD:** - **Price:** Gemini is cheaper at ~$0.012/1K chars vs OpenAI's ~$0.030/1K chars. - **Features:** Gemini's audio tags provide nuanced control lacking in OpenAI's simple speed adjustment. - **Latency:** Gemini has lower latency (<200ms vs ~300ms), benefiting real-time applications. - **Reliability:** OpenAI offers more stable long-form output; Gemini is still in preview with risks. - **Use Case:** Gemini is better for cost-effective, controllable short clips; OpenAI is preferable for basic, reliable TTS without expressive needs.

Community Feedback

Developers and researchers have praised Gemini 3.1 Flash TTS for its innovative audio tag system and cost-effectiveness. Many highlight its potential for rapid prototyping in accessibility tools, e-learning, and content automation. The sub-200ms latency has been noted as competitive for real-time use cases. However, concerns are widespread about its preview status and long-form instability. Reviews from sites like TTSAudit document severe quality degradation after one minute, warning against production use without testing. The lack of voice cloning and limited voice library are frequently cited as dealbreakers for brand-consistent or character-driven applications. Adoption is concentrated among startups and developers within the Google ecosystem, with many waiting for general availability and stability improvements.

Use Cases

1. **E-Learning and Training Narration:** Ideal for creating engaging educational content with expressive pacing and emotion. For example, a language-learning app can use audio tags like `[excited]` and `[slow]` to emphasize correct pronunciation, enhancing student engagement at minimal cost. 2. **Accessibility Tools:** Perfect for screen readers and assistive technologies needing clear, natural speech. A municipal government can generate multilingual public notices (e.g., in French or Spanish) with consistent, affordable audio, improving accessibility for visually impaired citizens. 3. **Content Automation for Podcasts and Videos:** Enables budget-friendly production of podcast intros, YouTube voiceovers, or video narrations. Content creators can use inline tags to add dramatic pauses or tone shifts, reducing reliance on expensive voice actors for short clips. 4. **Interactive Voice Applications:** Suitable for voice assistants or IVR systems requiring low-latency responses. A customer service bot can deliver fraud alerts with a `[serious]` tone followed by `[positive]` guidance, though real-time streaming is better handled by Gemini Live models.

Latest News

- **Release as Preview (April 15, 2026):** Gemini 3.1 Flash TTS launched via Google AI Studio, Gemini API, and Vertex AI, introducing audio tags for expressive control. - **Integration with Google Workspace:** Available in Google Vids for enterprise video narration, expanding use in business environments. - **SynthID Watermarking:** All output includes imperceptible watermarks for AI-content detection, addressing misinformation concerns. - **Ongoing Development:** Google has indicated continued iteration, with expectations for future pricing tiers, expanded voice libraries, and stability improvements for long-form content. - **Benchmark Recognition:** Ranked #2 on the Artificial Analysis TTS leaderboard, validating its short-form quality and controllability.

Positioned as a cost-effective alternative to premium TTS services, Gemini 3.1 Flash TTS excels in short-form applications like real-time narration, accessibility tools, and e-learning content. However, its preview nature and limitations in long-form stability and voice diversity position it primarily for prototyping and specific use cases where expressiveness and low cost outweigh production robustness needs.

Sources

Analysis generated: 2026-07-17